If a well is flowing uncontrollably (for example, if a blowout occurs), it can be extremely difficult to flow kill weight fluid into the well. In situations in which formation fluids are flowing rapidly into a wellbore and to the surface, it may be virtually impossible to force kill weight fluid into the wellbore at the surface (e.g., for either a land-based or subsea facility).
When a severe well control situation occurs, so severe that access to the wellhead and the ability to lower a string of drill pipe or tubing into the well that is blowing out, is impossible, typically the only option is to drill a relief well that intersects the out of control well below the last casing shoe at or above the zone where the borehole fluid influx is occurring, for the purpose of injecting “kill fluid” into the out of control well. This is a time consuming, expensive process, not without risk itself, nor is success 100% guaranteed.
Therefore, it will be appreciated that improvements are needed in the art of killing wells. Such improvements can also be useful in other operations, for example, while drilling and not killing the well.